A saturated carboxylic acid such as propionic acid (PA) can be catalytically reacted with formaldehyde (FA) in the vapor phase to produce an alpha, beta-ethylenically unsaturated carboxylic acid such as methacrylic acid (MA), and water. Catalysts to effect such reactions are well known in the art. See, for example, U.S. Pat. Nos. 3,014,958 to Koch et al.; 3,247,248 to Sims et al; 3,840,587 to Pearson; 3,933,888 to Schlaefer; 4,147,718 to Gaenzler; and 4,631,264 to Hagen. Such catalysts typically comprise a catalyst support and a catalytically active ingredient on the support. The produced unsaturated carboxylic acid can be esterified to a commercially useful unsaturated carboxylic acid ester such as methyl methacrylate (MMA).
MMA is a widely-used monomer. Illustrative of the many products that can be made from MMA-derived polymers are advertising displays, lighting fixtures, glazing materials, structural panels, and the like, molding resins for automobile tail-light lenses, plumbing fixtures, and the like, as well as constituents of a variety of surface coatings, adhesives, inks, floor polishes, and the like.
In carrying out most catalyzed chemical processes, catalysts are made in their final forms before being introduced into the process. However, it can be beneficial to produce the final catalyst form in situ. That is, produce it in the reactor as one or all of the process feeds are fed to the reactor, often under reaction conditions. Of course this technique is only useful if the catalyst made in this way is about equal to or superior to the catalyst made before introduction into the process. This requirement is a severe one as emphasized by the lack of catalysts produced in this way. Such an in situ produced catalyst, if a way is found to make it, can vastly improve economics, and, if the catalyst can be continually regenerated in the same way during the process, lifetime can be greatly extended with an additional resulting improvement in process economics.
The present invention provides a method for producing in situ an alkali metal ion-based catalyst for the condensation of formaldehyde and an alkanoic acid to form an alpha, beta-ethylenically unsaturated acid.